The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1 | /*--------------------------------------------------------------------------- |
| 2 | |
| 3 | rpng - simple PNG display program readpng.c |
| 4 | |
| 5 | --------------------------------------------------------------------------- |
| 6 | |
| 7 | Copyright (c) 1998-2007 Greg Roelofs. All rights reserved. |
| 8 | |
| 9 | This software is provided "as is," without warranty of any kind, |
| 10 | express or implied. In no event shall the author or contributors |
| 11 | be held liable for any damages arising in any way from the use of |
| 12 | this software. |
| 13 | |
| 14 | The contents of this file are DUAL-LICENSED. You may modify and/or |
| 15 | redistribute this software according to the terms of one of the |
| 16 | following two licenses (at your option): |
| 17 | |
| 18 | |
| 19 | LICENSE 1 ("BSD-like with advertising clause"): |
| 20 | |
| 21 | Permission is granted to anyone to use this software for any purpose, |
| 22 | including commercial applications, and to alter it and redistribute |
| 23 | it freely, subject to the following restrictions: |
| 24 | |
| 25 | 1. Redistributions of source code must retain the above copyright |
| 26 | notice, disclaimer, and this list of conditions. |
| 27 | 2. Redistributions in binary form must reproduce the above copyright |
| 28 | notice, disclaimer, and this list of conditions in the documenta- |
| 29 | tion and/or other materials provided with the distribution. |
| 30 | 3. All advertising materials mentioning features or use of this |
| 31 | software must display the following acknowledgment: |
| 32 | |
| 33 | This product includes software developed by Greg Roelofs |
| 34 | and contributors for the book, "PNG: The Definitive Guide," |
| 35 | published by O'Reilly and Associates. |
| 36 | |
| 37 | |
| 38 | LICENSE 2 (GNU GPL v2 or later): |
| 39 | |
| 40 | This program is free software; you can redistribute it and/or modify |
| 41 | it under the terms of the GNU General Public License as published by |
| 42 | the Free Software Foundation; either version 2 of the License, or |
| 43 | (at your option) any later version. |
| 44 | |
| 45 | This program is distributed in the hope that it will be useful, |
| 46 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 47 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 48 | GNU General Public License for more details. |
| 49 | |
| 50 | You should have received a copy of the GNU General Public License |
| 51 | along with this program; if not, write to the Free Software Foundation, |
| 52 | Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 53 | |
| 54 | ---------------------------------------------------------------------------*/ |
| 55 | |
| 56 | #include <stdio.h> |
| 57 | #include <stdlib.h> |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 58 | #include <zlib.h> |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 59 | |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 60 | #include "png.h" /* libpng header */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 61 | #include "readpng.h" /* typedefs, common macros, public prototypes */ |
| 62 | |
| 63 | /* future versions of libpng will provide this macro: */ |
| 64 | #ifndef png_jmpbuf |
| 65 | # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) |
| 66 | #endif |
| 67 | |
| 68 | |
| 69 | static png_structp png_ptr = NULL; |
| 70 | static png_infop info_ptr = NULL; |
| 71 | |
| 72 | png_uint_32 width, height; |
| 73 | int bit_depth, color_type; |
| 74 | uch *image_data = NULL; |
| 75 | |
| 76 | |
| 77 | void readpng_version_info(void) |
| 78 | { |
| 79 | fprintf(stderr, " Compiled with libpng %s; using libpng %s.\n", |
| 80 | PNG_LIBPNG_VER_STRING, png_libpng_ver); |
| 81 | fprintf(stderr, " Compiled with zlib %s; using zlib %s.\n", |
| 82 | ZLIB_VERSION, zlib_version); |
| 83 | } |
| 84 | |
| 85 | |
| 86 | /* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */ |
| 87 | |
| 88 | int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight) |
| 89 | { |
| 90 | uch sig[8]; |
| 91 | |
| 92 | |
| 93 | /* first do a quick check that the file really is a PNG image; could |
| 94 | * have used slightly more general png_sig_cmp() function instead */ |
| 95 | |
| 96 | fread(sig, 1, 8, infile); |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 97 | if (png_sig_cmp(sig, 0, 8)) |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 98 | return 1; /* bad signature */ |
| 99 | |
| 100 | |
| 101 | /* could pass pointers to user-defined error handlers instead of NULLs: */ |
| 102 | |
| 103 | png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); |
| 104 | if (!png_ptr) |
| 105 | return 4; /* out of memory */ |
| 106 | |
| 107 | info_ptr = png_create_info_struct(png_ptr); |
| 108 | if (!info_ptr) { |
| 109 | png_destroy_read_struct(&png_ptr, NULL, NULL); |
| 110 | return 4; /* out of memory */ |
| 111 | } |
| 112 | |
| 113 | |
| 114 | /* we could create a second info struct here (end_info), but it's only |
| 115 | * useful if we want to keep pre- and post-IDAT chunk info separated |
| 116 | * (mainly for PNG-aware image editors and converters) */ |
| 117 | |
| 118 | |
| 119 | /* setjmp() must be called in every function that calls a PNG-reading |
| 120 | * libpng function */ |
| 121 | |
| 122 | if (setjmp(png_jmpbuf(png_ptr))) { |
| 123 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 124 | return 2; |
| 125 | } |
| 126 | |
| 127 | |
| 128 | png_init_io(png_ptr, infile); |
| 129 | png_set_sig_bytes(png_ptr, 8); /* we already read the 8 signature bytes */ |
| 130 | |
| 131 | png_read_info(png_ptr, info_ptr); /* read all PNG info up to image data */ |
| 132 | |
| 133 | |
| 134 | /* alternatively, could make separate calls to png_get_image_width(), |
| 135 | * etc., but want bit_depth and color_type for later [don't care about |
| 136 | * compression_type and filter_type => NULLs] */ |
| 137 | |
| 138 | png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, |
| 139 | NULL, NULL, NULL); |
| 140 | *pWidth = width; |
| 141 | *pHeight = height; |
| 142 | |
| 143 | |
| 144 | /* OK, that's all we need for now; return happy */ |
| 145 | |
| 146 | return 0; |
| 147 | } |
| 148 | |
| 149 | |
| 150 | |
| 151 | |
| 152 | /* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error; |
| 153 | * scales values to 8-bit if necessary */ |
| 154 | |
| 155 | int readpng_get_bgcolor(uch *red, uch *green, uch *blue) |
| 156 | { |
| 157 | png_color_16p pBackground; |
| 158 | |
| 159 | |
| 160 | /* setjmp() must be called in every function that calls a PNG-reading |
| 161 | * libpng function */ |
| 162 | |
| 163 | if (setjmp(png_jmpbuf(png_ptr))) { |
| 164 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 165 | return 2; |
| 166 | } |
| 167 | |
| 168 | |
| 169 | if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD)) |
| 170 | return 1; |
| 171 | |
| 172 | /* it is not obvious from the libpng documentation, but this function |
| 173 | * takes a pointer to a pointer, and it always returns valid red, green |
| 174 | * and blue values, regardless of color_type: */ |
| 175 | |
| 176 | png_get_bKGD(png_ptr, info_ptr, &pBackground); |
| 177 | |
| 178 | |
| 179 | /* however, it always returns the raw bKGD data, regardless of any |
| 180 | * bit-depth transformations, so check depth and adjust if necessary */ |
| 181 | |
| 182 | if (bit_depth == 16) { |
| 183 | *red = pBackground->red >> 8; |
| 184 | *green = pBackground->green >> 8; |
| 185 | *blue = pBackground->blue >> 8; |
| 186 | } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) { |
| 187 | if (bit_depth == 1) |
| 188 | *red = *green = *blue = pBackground->gray? 255 : 0; |
| 189 | else if (bit_depth == 2) |
| 190 | *red = *green = *blue = (255/3) * pBackground->gray; |
| 191 | else /* bit_depth == 4 */ |
| 192 | *red = *green = *blue = (255/15) * pBackground->gray; |
| 193 | } else { |
| 194 | *red = (uch)pBackground->red; |
| 195 | *green = (uch)pBackground->green; |
| 196 | *blue = (uch)pBackground->blue; |
| 197 | } |
| 198 | |
| 199 | return 0; |
| 200 | } |
| 201 | |
| 202 | |
| 203 | |
| 204 | |
| 205 | /* display_exponent == LUT_exponent * CRT_exponent */ |
| 206 | |
| 207 | uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes) |
| 208 | { |
| 209 | double gamma; |
| 210 | png_uint_32 i, rowbytes; |
| 211 | png_bytepp row_pointers = NULL; |
| 212 | |
| 213 | |
| 214 | /* setjmp() must be called in every function that calls a PNG-reading |
| 215 | * libpng function */ |
| 216 | |
| 217 | if (setjmp(png_jmpbuf(png_ptr))) { |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 218 | free(image_data); |
| 219 | image_data = NULL; |
| 220 | free(row_pointers); |
| 221 | row_pointers = NULL; |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 222 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 223 | return NULL; |
| 224 | } |
| 225 | |
| 226 | |
| 227 | /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits, |
| 228 | * transparency chunks to full alpha channel; strip 16-bit-per-sample |
| 229 | * images to 8 bits per sample; and convert grayscale to RGB[A] */ |
| 230 | |
| 231 | if (color_type == PNG_COLOR_TYPE_PALETTE) |
| 232 | png_set_expand(png_ptr); |
| 233 | if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) |
| 234 | png_set_expand(png_ptr); |
| 235 | if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) |
| 236 | png_set_expand(png_ptr); |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 237 | #ifdef PNG_READ_16_TO_8_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 238 | if (bit_depth == 16) |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 239 | # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED |
| 240 | png_set_scale_16(png_ptr); |
| 241 | # else |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 242 | png_set_strip_16(png_ptr); |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 243 | # endif |
| 244 | #endif |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 245 | if (color_type == PNG_COLOR_TYPE_GRAY || |
| 246 | color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| 247 | png_set_gray_to_rgb(png_ptr); |
| 248 | |
| 249 | |
| 250 | /* unlike the example in the libpng documentation, we have *no* idea where |
| 251 | * this file may have come from--so if it doesn't have a file gamma, don't |
| 252 | * do any correction ("do no harm") */ |
| 253 | |
| 254 | if (png_get_gAMA(png_ptr, info_ptr, &gamma)) |
| 255 | png_set_gamma(png_ptr, display_exponent, gamma); |
| 256 | |
| 257 | |
| 258 | /* all transformations have been registered; now update info_ptr data, |
| 259 | * get rowbytes and channels, and allocate image memory */ |
| 260 | |
| 261 | png_read_update_info(png_ptr, info_ptr); |
| 262 | |
| 263 | *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr); |
| 264 | *pChannels = (int)png_get_channels(png_ptr, info_ptr); |
| 265 | |
| 266 | if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) { |
| 267 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 268 | return NULL; |
| 269 | } |
| 270 | if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) { |
| 271 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 272 | free(image_data); |
| 273 | image_data = NULL; |
| 274 | return NULL; |
| 275 | } |
| 276 | |
Chris Craik | ca2bf81 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 277 | Trace((stderr, "readpng_get_image: channels = %d, rowbytes = %ld, height = %ld\n", |
| 278 | *pChannels, rowbytes, height)); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 279 | |
| 280 | |
| 281 | /* set the individual row_pointers to point at the correct offsets */ |
| 282 | |
| 283 | for (i = 0; i < height; ++i) |
| 284 | row_pointers[i] = image_data + i*rowbytes; |
| 285 | |
| 286 | |
| 287 | /* now we can go ahead and just read the whole image */ |
| 288 | |
| 289 | png_read_image(png_ptr, row_pointers); |
| 290 | |
| 291 | |
| 292 | /* and we're done! (png_read_end() can be omitted if no processing of |
| 293 | * post-IDAT text/time/etc. is desired) */ |
| 294 | |
| 295 | free(row_pointers); |
| 296 | row_pointers = NULL; |
| 297 | |
| 298 | png_read_end(png_ptr, NULL); |
| 299 | |
| 300 | return image_data; |
| 301 | } |
| 302 | |
| 303 | |
| 304 | void readpng_cleanup(int free_image_data) |
| 305 | { |
| 306 | if (free_image_data && image_data) { |
| 307 | free(image_data); |
| 308 | image_data = NULL; |
| 309 | } |
| 310 | |
| 311 | if (png_ptr && info_ptr) { |
| 312 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 313 | png_ptr = NULL; |
| 314 | info_ptr = NULL; |
| 315 | } |
| 316 | } |